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Trailers, Brakes and Common Usage Errors

I perform audits of both utilities and contractors. When I work with them to do those audits, we include trucks and trailers. The trailers I’m talking about here are not the box vans behind tractors, but the general-duty trailers used to haul trenchers, backhoes, wire reels and padmount transformers. It’s no surprise that the trailer issues we discover are in keeping with the types and frequencies of violations that enforcement officials find on the roadways: those involving lights, load securement and brakes. Auditors also get a lot of questions about trailer safety, or more specifically, trailer rules, which are in place for trailer safety. I almost always receive those questions after an enforcement action has occurred.

Many enforcement actions have come about due to the efforts of states that have noticed trends in trailer-related incidents. The incidents didn’t involve semi-trailers pulled by tractors; they involved smaller trailers used in commercial environments where enforcement had not spent much focus. Without that focus, there was a lack of accountability, and now it’s caught up with us. States are enhancing their observations of commercial trailering, making stops and taking trailers out of service for numerous issues, most often related to brakes.

The inspiration for this article was a recent training visit I made to a central U.S. utility. On the way to the training location, I saw a utility crew on the side of the road with a state trooper. It turned out they were my training class for that day, so I got to ask them about the stop. It was about brakes. The trooper was getting ready to pull out from a doughnut shop (really, he was) when the crew passed in front of him. The trooper noticed the lack of a battery box and a battery, so he stopped them. He didn’t check to see whether the brakes were working because the lack of a battery on the electric braking system meant the breakaway emergency system wasn’t functional. The crew got a ticket, but they also caught a break. Since the yard was two blocks away, the state trooper allowed the crew to continue to the yard instead of putting them out of service. He also stopped by later that afternoon to see if the trailer brakes had been repaired. They had been.

Once during an audit, I came across a contract line crew with a malfunctioning pole-trailer braking system. The reason I knew it was malfunctioning was because the blue wire in the trailer’s electrical plug was pulled out of the plug and very noticeably hanging from the cord. The reason for that, the crew explained, was that the trailer brakes had locked up and wouldn’t release. They had to get 70 poles delivered to the right-of-way before the day was over, so they had no choice but to disconnect the brakes and “just be careful.” There are several unacceptable issues here, but the worst likely was not the crew’s fault. There were five crew members who held commercial driver’s licenses: one truck driver, two apprentices and three journeymen. This was not a fly-by-night operation, but for all the company did right, not one person on the crew realized the gain was dialed all the way up on the controller in the cab. That’s why the brakes locked up.

How many crews does your company send out with equipment they are not familiar with? How many crew members in your company will solve a problem like stuck brakes in a similar way? As we say at the Institute for Safety in Powerline Construction (ISPC), even the very best programs you create are only as good as the training you conduct when you roll them out. To me, the issue with brakes is seriously overlooked and underrated. Big trucks handle very poorly in emergency maneuvers, and almost nothing makes an emergency more unmanageable than a 10-ton trailer pushing a truck where the driver doesn’t want to go.

Brakes Are Required
Federal Motor Carrier Safety Regulation 393.42 is the rule on brakes. Any trailer over 3,000 pounds is required to have brakes. Trailers under 3,000 pounds must have brakes if the trailer axle weight exceeds 40% of the combined axle weight of the tow vehicle. The under-3,000-pounds rule and the 40% rule likely won’t apply in the line industry unless we get carried away with this electric truck thing. Trailers used in the line industry typically exceed 3,000 pounds.

While we are on this topic, I want you to take safety home with you, so keep in mind that an 18-foot fiberglass boat with a single outboard motor on a trailer typically weighs over 3,000 pounds. Since safety is the reason for brakes, it’s a safety issue if your boat trailer’s brakes are not functional or properly adjusted, even if enforcement doesn’t check privately owned trailers not used in commercial operations. Privately owned trailer crashes are just as deadly as commercial trailer wrecks.

Now, back to big trucks, trailers and brakes. In addition to brakes, the trailer must have an emergency breakaway system that applies the brakes in the event the trailer becomes disconnected from the tow vehicle. Electric braking systems use a controller that supplies 1 to 12 volts into the actuator system that delivers a proportional magnetic or hydraulic applied friction brake to the trailer wheels. On the electric system, a breakaway-system battery mounted on the trailer is actuated by a lanyard connected to a switch. If the trailer breaks away, the lanyard is pulled, activating the switch that applies the full battery voltage to the actuator, locking the brakes on the trailer.

Trailer surge brakes use the weight of the trailer against a hydraulic piston mounted in line with the trailer tongue to proportionally apply braking pressure to the trailer’s wheels. The emergency breakaway on a surge system uses a master cylinder actuated by a lanyard that applies full brake pressure to the trailer brakes. Now, not new but not as familiar are electric-over-hydraulic trailer-braking systems that use a combination of proportional electrical signal to hydraulic pressure device, usually a motor that produces the hydraulics to the drum or disc brakes. But as I wrote earlier, even the best systems that are periodically inspected and maintained by good mechanics are only as good as the training of the people who use them. That is often where we find issues in audits and roadside inspections. And speaking of roadside inspections, I’m aware of two recent reports of the Department of Transportation using empty school parking areas to pull over trucks with trailers for brake tests. Using the requirements of the table found in FMCSR 393.52, they set up a brake test zone and have the driver demonstrate the stopping ability of the loaded trailer.

Four Common Trailering Errors
So, with that message delivered about trailer brakes, here are four common trailering issues to be aware of:

1. Overloading the Trailer
With lineworkers, the policy often is, “if it fits, it flies.” This is not an uncommon problem. I sometimes remind lineworkers that when they are loading, securing and driving trucks, they are not lineworkers – they are CDL truck drivers. They know the rules, or at least they knew the rules when they qualified for their CDL. That’s not a criticism of lineworkers as much as it is a deserved criticism of employers. Of all the posters and safety topics you see in a year, how many are dedicated to calculation or review of trailering and trailer loads? On several occasions, I have heard lineworkers assume that if they gave me this trailer and these two 15,000-pound reels of wire, they must fit.

Recommendation: Periodically review trailering, load securement, calculations and weight labels. Even better, stencil axle ratings and load limits on trailer tongues for ready information access for crews.

2. Load Securement
Securement devices are called out in FMCSR 393.104. I frequently find loads secured with straps and chains or binders rigged over lightweight side rails that already are bent from previous tie-downs. These rails will bend further or fail during what should have been a manageable emergency maneuver. When rails fail, the load shifts, creating dynamic forces that can result in loss of trailer control.

Recommendation: Fleets should conduct periodic training on and reviews of load securement and rigging equipment for crews. In addition, they should ensure appropriate tie-downs compatible with issued rigging equipment are available at multiple points on trailers. Even better, paint designated tie-downs with contrasting paint so they are easily visible to operators.

3. Trailer Breakaway Check (FMCSR 393.43)
I have never found a crew that has performed a trailer breakaway test. Trailer breakaway systems are required to be applied for 15 minutes post-breakaway. To test the system, a worker actuates the breakaway lever while a second person listens for or observes the actuation of the armatures on the trailer and then times it out. If a battery does not maintain a charge for 15 minutes, it likely needs to be replaced. If hydraulics fail to maintain the brake for 15 minutes, the system is probably leaking. Either way, the system failed and will not perform in a breakaway or roadside inspection.

A related issue is that the brakes are not always properly functioning even though most braking systems automatically adjust. When ISPC audits utilities, we have drivers roll slowly ahead and manually apply the trailer brake controller to test the brakes. Occasionally we find drivers who don’t know how to do that. On rare occasions we find brakes that don’t work properly. If that’s the case, even if the breakaway works, it’s not going to stop the lost trailer from hitting that school bus. Trailer brakes and breakaway systems are part of a daily DOT driver’s inspection, but we rarely find the trailer getting the scrutiny given to the truck.

Recommendation: In your inspection documents, include prompts to periodically examine braking systems and conduct breakaway checks.

4. Trailer Connection Safety Chains
This gets confusing because of some clarity issues in the FMCSR. General-use trailers are covered in FMCSR 393.70(d). A reading of that paragraph makes it sound as though it only applies to semi-trailers and tow-dollies except for one “shall” reference in 393.70(d)(6) that references “tongue eye or other hitch device.” General-use trailers are “semi” trailers, meaning the rear is supported on its own axle and at least some of the load is supported by the towing vehicle. When it comes to securement devices, typically chains, this rule prevails. Some people also read FMCSR 393.71(h)(10)(ii) that requires crossed chains and think it applies to our trailers. It does not. There is nothing wrong with crossed chains, but in this case, the rule only applies to hinged tow bars used in drive-away/tow-away operations. The rule that applies to utility trailers – 393.70(d)(6) – does not require chains to be crossed. In fact, it doesn’t even require two chains. Two chains usually are used to meet the strength requirement of the rule. Strength of the chain is not spelled out, but it is required that the chain provide strength, security of attachment and directional stability. Strength is defined in rule 390.70(d)(3) as not less than the gross weight of the vehicle being towed, and that includes the means of attachment of the chain to the trailer tongue. I once found a 7/16th-inch safety chain pair connected to a trailer tongue with a 5/16th crossarm carriage bolt. I think that’s what the rule was intended to prevent.

Whether you cross them or not, here is what the chains are to accomplish in simple language:

  • They should be strong enough to hold the trailer in case of disconnect.
  • They should only be long enough to allow turns.
  • They should be short enough that the tongue will not strike the ground if disconnected.
  • They should be reliably connected to the towing vehicle.
  • If one chain is used, it must be attached to the right of the centerline to prevent the tongue of the trailer from projecting into oncoming traffic in case of a disconnect.

A Final Piece of Advice
Here is my final advice that also comes from experience. When I bring up these issues to utilities and contractors, I often get pushback because there have not been instances of these issues causing incidents in their fleet. That may be true, but it is worth noting that these rules were established after considerable review and debate among industry professionals. It’s also important to realize that most of these rules were developed in post-incident investigations. Crashes are not caused by the parts that work correctly.

About the Author: After 25 years as a transmission-distribution lineman and foreman, Jim Vaughn, CUSP, has devoted the last 22 years to safety and training. A noted author, trainer and lecturer, he is a senior consultant for the Institute for Safety in Powerline Construction. He can be reached at

Train the Trainer 101

Jim Vaughn, CUSP

After 25 years as a transmission-distribution lineman and foreman, Jim Vaughn, CUSP, has devoted the last 24 years to safety and training. A noted author, trainer and lecturer, he is a senior consultant for the Institute for Safety in Powerline Construction. He can be reached at